Pheochromocytomas and paraganliomas (PPGLs) are neural crest-derived tumors with variable aggressiveness. Over 10% of PPGLs patients have malignant disease at their first surgery with a 5 year survival of >50% (Eisenhofer, et al. 2004). The development of malignancy and the underlying molecular pathways in PPGLs are poorly understood and efficient treatment strategies are missing. Marine sponges provide a natural source of promising anti-tumorigenic and anti-metastatic agents. The present study evaluates the anti-tumorigenic and anti-metastatic potential of Aeroplysinin-1 (García-Vilas, et al. 2015), a secondary metabolite isolated from the marine sponge Aplysina aerophoba, on mouse pheochromocytoma cells (MTT).
Aeroplysinin-1 decreased cell viability (EC50 = 11.4 µM) and induced apoptosis in a concentration dependent manner. Moreover, treatment with Aerolysinin-1 diminished the number of proliferating cells (2D-culture) and reduced spheroid growth (3D-culture) significantly. The influence of Aeroplysinin-1 on pro-metastatic behavior was analyzed using Boyden Chamber assays. Aeroplysinin-1 decreased the migration ability of the cells significantly (P = 0.01), whereas, the invasion capacity was not affected. MTT cells showed a low adhesion affinity to the extracellular matrix protein fibronectin that is mildly affected by treatment with Aeroplysinin-1. In contrast, Aeroplysinin-1 significantly diminished the high adhesion capacity of the MTT cells to collagen (P < 0.001) and, furthermore, reduced the ability to form spheroids significantly. Ongoing investigations indicate a regulative influence of Aeroplysinin-1 on the expression of the different integrins and cadherins, potentially explaining the inhibitory effects of Aeroplysinin-1 on pro-metastatic behavior.
These in vitro investigations show promise for the application of the sponge-derived marine drug, Aeroplysinin-1 as anti-tumorigenic and anti-metastatic drugs against PPGLs. Furthermore, screening of other sponge-derived secondary metabolites provides an auspicious strategy to identify novel therapeutic strategies for metastatic PPGLs.